The factors to be considered for evaluating the suitability of a cable for a particular application are load, system voltage, cable insulation, short circuit rating, environmental conditions, sheath and protective coverings, heat dissipation losses, economic considerations etc. The following points are important Maximum continuous current rating System Earthing Voltage drop Conditions of installation Expected Short … Read more
In power distribution system both aluminium and ACSR are commonly used. Mostly aluminium conductors are used in the distribution system because of cheaper in cost. Some of the factors which decide the size of the conductors designed for distribution system are given below: Current carrying capacity of the conductor or distribution line Allowable voltage drop … Read more
DC transmission is an effective means to improve dynamic system performance. HVDC transmission consists of two converter stations which are connected to each other by a DC cable or an overhead DC line. By varying the firing angle (α), the DC output voltage can be controlled thereby controlling the power flow. In DC transmission, the … Read more
Many have you seen a string of circular disc like structure on transmission line structure as shown below. Some are hanging vertically and some are horizontally arranged. These are called Overhead line insulators. Fig. Overhead Line Insulators Overhead Line Insulators are used to separate line conductors from each other and from the supporting structures or … Read more
DC machine whether it is motor or generator will have four essential parts. They are Field System Armature Commutator Brush and Brush gear 1. Field System The objective of field system in DC machine is to provide uniform magnetic field, within which armature rotates. For small rating motors permanent magnets are used and for large … Read more
AC power has become popular and advantageous because of easy generation, transmission with fewer losses to long distances due to stepping up voltage and stepping down the voltage to the desired level. In Industries 70% of the motors and drives used are Induction motors, hence ac motors in general means induction motors. Induction motors were … Read more
Traction is defined as ‘the act of drawing or pulling especially by a motive force‘ (drawing of carriage by horse constitute traction). In mechanical terms, it is defined as the ‘adhesive friction between the wheel and the surface on which it moves‘ (between a car tire and road). Traction system can be broadly classified as … Read more
Braking in DC motor is employed to make the dc motor to halt from operating condition by applying a brake. It is to be considered that significant difference exists between the words ‘braking’ and ‘breaking’, should not get confused. In dc motors we apply the brake to make the dc motor halt. Different braking methods … Read more
In DC series motor field coils or winding will be in series with the armature winding. The conductor size of the field winding will be having a thick wire (large cross section) with lesser turns. Advantages of DC Series Motors The main application where series motors are best suited is for traction applications. The torque … Read more
In spite of the wide use of AC supply, DC machines have some advantages compared to ac motors and are used in industries for some applications. Some of the DC Motor Applications in Industries are listed below. Applications of DC Series Motor DC series motors are widely used for electrical traction applications, i.e, these motors … Read more
